Apple's self-driving car program has seemed for years to be one of the industry's worst-kept secrets. Between the weird lump-like shape that ended up on the cover of Motor Trend and the sensor-rig equipped test cars that have been spotted all over California, the secret is out but what exactly is Apple doing and why is it doing it so slowly?

Thanks to the California DMV (and MacReports), we know that Apple currently has a fleet of 55 vehicles, up from 27 in January, registered for autonomous testing with human safety drivers on public roads. We also know that the company has 83 drivers that are certified to serve as the safety drivers for these cars. Interestingly, Apple has not applied for one of California's new fully driverless autonomous testing permits.

This photo appears to show the sensor array on top of an Apple self-driving car.

MacCallister Higgins

So, we know that Apple has cars and safety drivers, what we don't know is what exactly its been doing with them. See, California requires all companies performing autonomous vehicle testing within its boundaries to submit what is called a "Vehicle Disengagement Report" that outlines both the number of times that a human driver had to intervene and wrest control from the car, and the circumstances surrounding these interventions, aka disengagements. Apple only received its permit to test in April of 2017, and thus doesn't have to file one until January of 2019.

The current belief is that rather than offer the public an "Apple car," it will license its self-driving car technology to other manufacturers, something that seems a little different for Apple, a company that is known for keeping a tight leash on its intellectual property and closely controlling its image.

There is definitely a non-zero chance that these two are testing self-driving cars in a volcano lair.

Justin Sullivan/Getty Images

What exactly are Tim Cook and Jony Ive up to? Are they testing the Apple self-driving cars in some secret volcano lair off of the Northern California coast, gliding around in electric silence broken only by fits of maniacal laughter and occasional geological rumbling? Who can say?